The invention herein pertains to the field of flowable herbicides. The invention particularly relates to a water-based flowable herbicidal mixture containing 2-chloro-N-isopropylacetanilide (commonly referred to as propachlor) and s-triazine herbicides, e.g., atrazine, as the active ingredient.
Mixtures of propachlor and s-triazine herbicides are known in the art. For example, U.S. Re. Patent No. 26,961 (original U.S. Pat. No. 2,863,752) and U.S. Pat. Nos. 3,442,945 and 3,547,620 describe various 2-haloacetanilides, e.g., propachlor, alachlor, butachlor, etc., which may be used alone or in admixture with herbicides including various triazines, including s-triazines. U.S. Pat. Nos. 2,891,855 and 2,909,420 describe various triazines, e.g., atrazine, and Canadian Pat. No. 847,250 refers to the combination of certain s-triazines with alachlor in various forms, e.g., solutions, emulsions suspensions, or dusts. However, this patent does not give any details as to the materials (except active ingredients) or processes for producing any of these forms of formulations.
Commercial formulations of flowable 2-chloro-N-isopropylacetanilide (propachlor) are known in the art; for example, a four pound per gallon propachlor flowable formulation is commercially available under the trade name "Bexton 4L" from the Dow Chemical Co., P. O. Box 1706, Midland, Mich. 48640. A flowable atrazine formulation is commercially available under the trade name "Amtrex 4L" from Ciba-Geigy Corp, Basle, Switzerland.
A flowable herbicide formulation may be defined as a physical mixture which contains a finely divided solid or a liquid, suspended in a liquid dispersing medium. A flowable herbicide formulation has advantages over, for example, wettable powder formulation since wettable powder herbicide formulations must be converted into slurries to be used by the farmer in preparing tank mixes for application to the soil. The preparation of slurries of wettable powders of some herbicides, e.g., propachlor, presents certain safety hazards and inconveniences due to the generation of noxious dusts which are irritating to the skin and hazardous to breathe. In addition, wettable powder formulations of propachlor, when prepared as tank mixes, may not disperse well and may also have problems of suspensibility, redispersibility and compatibility with liquid fertilizers.
An emulsifiable concentrate, which is a formulation of the active ingredient dissolved in an organic solvent plus emulsifiers avoids many of the problems of wettable powders, i.e. hazards of noxious dusts, suspensibility and dispersibility problems.
However, water-based flowable herbicide formulations have advantages over emulsifiable concentrates since the latter utilize organic solvents which may be flammable and/or toxic and the cost of which is tied to the cost of oil which continues to escalate.
Additionally, most higher-melting solid herbicides, particularly those with limited solubility in water or organic solvents, have been particularly difficult to formulate in other than wettable powder-type forms. In contrast to emulsifiable concentrates, which rely on ready solubility of the technical active ingredient in a suitable organic solvent such as xylene, chlorobenzene, etc., several herbicides, including propachlor and atrazine, have low to moderate solubility in any solvent, organic or aqueous and, thus, are not conveniently formulated as emulsifiable concentrates.
Accordingly, it is a particular object of the present invention to provide a water-based, flowable propachlor/s-triazine, herbicide composition which may be prepared, transported, stored and used as a one-container herbicide having none of the disadvantages of wettable powder and emulsifiable concentrate formulations.